1. Field of the Invention
The present invention relates to the field of communications in the interactive television environment and specifically relates to a method and apparatus for providing a generic meta language and digital television application protocol for interactive television.
2. Summary of the Related Art
Interactive television systems can be used to provide a wide variety of services to viewers. Interactive television systems are capable of delivering typical video program streams, interactive television applications, text and graphic images, web pages and other types of information. Interactive television systems are also capable of registering viewer actions or responses and can be used for such purposes as marketing, entertainment and education. Users or viewers may interact with the systems by ordering advertised products or services, competing against contestants in a game show, requesting specialized information regarding particular programs, or navigating through pages of information.
Typically, a broadcast service provider or network operator generates an interactive television signal for transmission to a viewer's television. The interactive television signal may include an interactive portion comprising of application code or control information, as well as an audio/video portion comprising a television program or other informational displays. The broadcast service provider combines the audio/video (A/V) and interactive portions into a single signal for transmission to a receiver connected to the user's television. The signal is generally compressed prior to transmission and transmitted through typical broadcast channels, such as cable television (CATV) lines or direct satellite transmission systems.
Typically, the interactive functionality of the television is controlled by a set top box (STB) connected to the television. The STB receives a broadcast signal transmitted by the broadcast service provider, separates the interactive portion of the signal from the A/V portion of the signal and decompresses the respective portions of the signal. The STB uses the interactive information, for example, to execute an application while the A/V information is transmitted to the television. The STB may combine the A/V information with interactive graphics or audio generated by the interactive application prior to transmitting the information to the television. The interactive graphics and audio may present additional information to the viewer or may prompt the viewer for input. The STB may provide viewer input or other information to the broadcast service provider via a modem connection or cable.
In accordance with their aggregate nature, interactive television systems provide content in various content forms and communication protocols the must be understood and displayed by the STB/client that receives the information from the broadcast service provider/network operator. Typically the client is a STB having a processor possessing limited processing power. Translation of the various contents and protocols is beyond the limited processing capability available in the typical STB processor. Thus there is a need for a simple communication protocol which can be easily understood by the client/STB processor and communicate in the various protocols used by service providers.